wickchart-replay

Bar replay for wickchart, as an opt-in plugin — the core stays replay-free. Zero dependencies, zero core changes: the whole engine runs on the public data API (setData + update).

Play history forward bar-by-bar or at speed while the future stays hidden. A badge layer shows the mode and position at a glance.

npm install wickchart wickchart-replay   // the plugin is a separate package

import 'wickchart';                        // the chart itself
import { attachReplay } from 'wickchart-replay';

const chart = document.querySelector('wick-chart');
const replay = attachReplay(chart);

replay.start();                 // head defaults to ~70% of the data
replay.start(1772604000000);    // …or a time (ms, seconds, or a date string)
replay.start(42);               // …or a bar index (integer < data length)
replay.step();                  // reveal one bar (step(5) reveals five)
replay.play();                  // 4 bars/sec (default), pause at the end
replay.play(15);                // faster; setSpeed(v) works while playing
replay.pause();
replay.seek('2026-03-06');      // jump the head — also activates when idle
replay.setLoop(true);           // wrap to the anchor instead of pausing
replay.stop();                  // exit — the full dataset is restored
replay.detach();                // …and stop() + remove the layer

// progress readout
chart.addEventListener('wick:replay', (e) => {
  const d = e.detail;
  status.textContent = d.active ? `${d.index + 1}/${d.total}` : '';
});

• Anchors: start/seek accept a bar index (integer < data length), a timestamp (ms or seconds — anything ≥ 1e9), or a date string; null defaults to ~70% of the data; unresolvable values fall back to the default.
• State: active, playing, loop, index, total, time, speed getters; every change fires wick:replay with the full snapshot.
• Loop: setLoop(true) wraps back to the anchor at the end of the data instead of pausing.
• Live feeds: pause them while replaying. An external update() or setData() during replay means the data moved under the plugin — replay aborts (without restoring) rather than corrupting the chart. The wickchart demo stops its feed automatically when you press Replay.
• Paper trading and an equity curve are the planned 0.2 follow-up; the replay engine (this package) is intentionally data-only.

Peer dependency: wickchart ≥ 1.4.0.